The listing or discussion of an apparently prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.
Background
Dysfunctional redox regulation of cellular signalling and an increased ROS (Reactive oxygen species) tension have been demonstrated to play a crucial role in cancer etiology, progression and metastasis (Zhang et al., Antioxid Redox Signal 15(11)2011:2876-2908). ROS mediates tumor-promoting characteristics, such as e.g. unrestrained proliferation, survival signaling, increased migration, angiogenesis. ROS are generated during cell metabolism and are highly reactive with macromolecules such as DNA, proteins and lipids. Exposure of nucleic acids to ROS can create more than 20 oxidatively modified nucleotides, of which 8-oxo-7,8-dihydroxyguanine (8-oxo-dG) is most abundant. 8-oxo-dG plays a pivotal role in mutagenesis (Sekiguchi and Tsuzuki, Oncogene 21(58)2002:8895-906). To protect themselves from carcinogenic effects, mammalian cells are armed with a set of repair enzymes to remove the oxidized nucleotides to maintain genome integrity. One of these protective enzymes is MTH1 (MutT homologue 1, 8-oxo-dGTPase, NUDT1). Interestingly, MTH1 is upregulated in various cancer forms, suggesting that the cancer cell rely on MTH1 function to survive the increased DNA lesion (Human Proteinatlas, Koketsu et al., Hepatogastroenterology, 51(57)2004:638-41). Suppression of MTH1 level and activity by using RNAi technology, leads to reduced cancer cell survival, premature senescence and DNA strand breaks (Rai et al, PNAS, 106(1)2009:169-174), Helleday et al unpublished data). Interestingly, lung cancers which spontaneously form in OGG−/− mice are prevented from forming in crosses with the MTH1−/− mice, suggesting that MTH1 is required for lung cancer cells to survive (Sakumi et al., Cancer Res 63, 2003: 902). We have observed that downregulation of MTH1 protein levels in human colon cancer tumors in xenograft mice model reduced tumor growth and significantly shrinked the tumour (Helleday et al, unpublished data).
In tumour cells, reducing the capacity to eliminate oxidised dNTPs by inhibiting MTH1 activity, will reduce cancer cell survival and hence be a promising novel anticancer therapy, either as monotherapy in cancer forms with high oxidative stress levels and/or in combination with radiotherapy and chemotherapy drugs.
Shortcomings and Complications with Current Treatment
Today's treatment of cancer is not effective for all patients with diagnosed disease also including a large proportion of patients that experience adverse effects from treatments with existing therapies or where resistance to on-going therapy is developed over time.
Prior Art
Engelhardt, H. et al. Journal of Medicinal Chemistry (2013), 56(11), 4264-4276 and US patent application US 2010/0016344 disclose certain 6-aryl-2,4-diaminopyrimidines having an additional pyrimidine appendage as histamine H4 receptor modulators. The compounds are claimed to be useful for a various diseases including cancer pain, but their use in the treatment of cancer as such is neither disclosed or suggested.
International patent application WO 2013/066839 discloses 6-(3-pyridyl)-(2,4-diaminopyrimidines as HDAC inhibitors. However, the substituent on the 4-amino group contains a prerequisite 5-trifluoromethyl-1,2,4-oxadiazol-3-yl group. 2,4-Diaminopyrimidines substituted in the 6-position with 3-aminoindazoles have been described in international patent application WO 2010/059658. Although also indazoles without the amino groups are mentioned, it is evident from the examples that the 3-amino substituent on the indazole is required for activity. The same document also describes 2,4-diaminopyrimidines substituted in the 6-position by a 3-cyano-2-fluorophenyl group. However, these compounds are merely precursors to the 3-aminoindazoles mentioned above and there is no disclosure or suggestions in the document that they possess any anti-cancer activity.
International patent application WO 2006/078886 describes 2,4-diaminopyrimidines substituted in the 6-position by an aryl group as wnt modulators. The 4-aryl group is lacking any substituents or must be substituted in the 3-position by methoxy. The document does not disclose or suggest compounds with any other substituent-pattern, nor does it mention or suggest the use of such compounds in the treatment of cancer. Moreover, in all examples the 4-amino group of the pyrimidine is substituted by either 1,3-benzodioxol-5-ylmethyl or by 4-hydroxy-phenethyl. Several scientific publications describe the use of one of the compounds (N4-(1,3-benzodioxol-5-ylmethyl)-6-(3-methoxyphenyl)-2,4-pyrimidinediamine) as a tool to investigate the wnt-pathway.
International patent application WO 86/04583 describes aziridinyl substituted anti-neoplastic compounds. There is only one compound that has both a 6-aryl substituent and a 4-N-alkyl group attached to 2-aminopyrimidine core. The compound has besides the aziridinyl group a fluorine in the 5-position of the pyrimidine ring. Both the aziridinyl and the fluorine are implied to be important for the activity and there is nothing that suggests that anti-neoplastic activity can be obtained without at least one of these substituents.
British patent application GB 681712 describes 2,4-diaminopyrimidines substituted in the 6-position by an aryl group for use in the treatment of cancer, but in only one example the aryl is phenyl and the 4-amino group is substituted by an alkyl. In this compound the phenyl is unsubstituted and the alkyl is methyl.
There is no disclosure in this documents of compounds in which the 6-phenyl may be substituted by other groups than chloro or nitro in the para-position, that the 6-phenyl may contain more than one substituent or that the 4-alkylamino-group is larger than methyl or may carry substituents.
Two publications from the group of H. Junjappa (Indian Journal Chemistry (1985), 24B 466; Synthesis (1980), 748) describe the synthesis of certain 2-amino-4-(N-alkylamino)-6-arylpyrimidines. The publications do not mention or suggest the use of the synthesized compounds in the treatment of cancer.
There are numerous 2-amino-4-(N-alkylamino)-6-arylpyrimidines that are, or that at some point have been stated to be, commercially available but that do not have any ascribed pharmaceutical use, nor any other use, ascribed to them.
MTH1 inhibitors have been described in Streib, M. et al. Angewandte Chemie, Int., Ed. (2013), Vol. 52. The compounds are organometallic and are not 2-amino-4-(N-alkylamino)-6-aryl pyrimidines.